Polyolefins such as polyethylene and polypropylene are widely used in industry for packaging, plastic films, containers, bottles and automotive components. Their excellent chemical resistance, electrical insulation, toughness and flexibility make them extremely important in industry.
Nanocomposites of polyolefins with nanoscale inorganic fillers are potentially of great importance as the presence of dispersed nanoparticles can improve their properties (such as mechanical strength or thermal stability) which cannot be obtained by a simple macroscopic mixing of polymer with bulk inorganic materials. However, obtaining a high degree of dispersion of inorganic nanoparticles in a polyolefin matrix has always been a challenge. It has been demonstrated that the surface functionalization of inorganic nanoparticles with polymer brushes (especially polymers of the same type as the nanocomposite matrix) can drastically improve the dispersion of nanoparticles within the matrix.
Inorganic nanoparticles with huge surface area and low cost have been widely used to reinforce polyolefin composites, such as their heat resistance, low strength, optical properties, etc. However, the fabrication of polyolefin-like functionalized inorganic nanoparticles is a major challenge. Free radical polymerization is unable to synthesize polyolefins with control over molecular weight and polydispersity. With controlled radical polymerization (CRP) techniques, control over chemical composition, grafting density, molecular weight, molecular architecture, and polydispersity can be achieved. However, most of the CRP methods do not allow polymerization of polyolefins on the surface of nanoparticles, such as polyethylene and polypropylene.
As such, a need exists for an improved polyolefin nanocomposite with good dispersion of nanoparticles at both high and low nanoparticle loading.